Acme Engineering Prod. Ltd.

- Model REF-IR-ST - VOC-2 - Volatile Organic Compounds Detector



The Acme Volatile Organic Compounds Detector, REF-IR-ST Sensor/Transmitter, is designed to detect the presence of refrigerant leaks in enclosed areas. The REF-IR-ST series employs a high-precision NDIR sensor ideal for gas-specific and accurate measurements of the most commercially used refrigerants. With its 1PPM resolution, 0-1000PPM measuring range and operating temperature and humidity characteristics, the REF-IR-ST far exceeds the current ASHRAE 15 requirements. The diffusion-based sensing method eliminates the use of filters and moving parts such as pumps, solenoid valves, etc. found in sample-draw systems and renders virtually maintenance-free operation.

The REF-IR-ST addressable version is fully compatible with Acme’s popular CEL-Series Multipoint Controllers making refrigerant leak monitoring possible from a single control panel and up to 32 transmitters in a common RS-485 network. The REF-IR, on the other hand, is a singlepoint stand-alone refrigerant leak Sensor/ Controller available either with a built-in or a remote sensor. The standard unit has a 3-stage relay output and an alarm buzzer. REF-IR-24 operates from a dedicated 24V 60HZ power supply source. Optionally it can also provide a 4-20mA output and can be equipped with a strobe light. Units are also available for 120V 60HZ power supplies (REF-IR-120).

Indoor air quality problems, known as 'Sick Building Syndrome' have become issues of health and comfort in new and recently remodeled buildings. Buildings are called 'Sick' when their occupants experience symptoms such as headaches; eye, nose and throat irritation; dizziness; nausea; sensitivity to odors; and difficulty in concentrating.

Frequently encountered IAQ problems are caused by elevated indoor pollutants such as VOCs (Volatile Organic Compounds) and ineffective ventilation systems in buildings.

VOC emanations (such as toluene), are released by synthetic materials, cleaners, printers, paints, etc.

Once the VOC-2 detects concentrations in excess of calibrated levels, it demands ventilation and/or signals an audible alarm. The VOC-2 can be installed in stagnant areas of buildings where pollutant concentrations will rise. Standard units are calibrated using toluene. Units can also be calibrated with other compounds specified by the customer.

  • Fully electronic system with solid state circuitry and built-in sensor.
  • Compactcorrosion resistant gasketed enclosure.
  • Two factory calibrated operating levels (Low & High) with visual indicators.
  • Suitable for ventilation control.
  • Audible alarm.
  • High sensitivity and stability.
  • Temperature compensated. High long-term reliability. Can be mounted on a wall or on a column.

  • Gases detected: Toluene, hexane, benzene, xylene
  • Sensor: N-type Metal Oxide Semiconductor (MOS)
  • Mounting: Wall or column with brackets (supplied)
  • Unit dimensions: 152mmH x 152mmW x 101mmD (6”H x 6”W x 4”D)
  • Supply voltage: 120V AC (Also available 24 or 220V AC) 50-60 Hz, 20VA
  • Ambient Temp.: 10-40º C (50-100º F)
  • Dry control contacts: 2
  • Contact rating: 5A @ 120V AC 1PH
  • Contact relay 1: Low Level
  • Contact relay 2: High Level
  • LED indicators: Power On, Low Level, High Level
  • Options: Pneumatic sampling : Cat. No.: VOC-2-EN

Principle of operation

The ACME VOC-2 uses a tin dioxide (SNO2) semiconductor gas sensor designed to detect volatile organic compounds. The decrease of electrical resistance of the sensor as it gets exposed to gases or vapors is used as an electrical output signal for detection.

There are two operating levels in the VOC- 2. At the LOW level the unit will activate a SPDT relay contact. At the HIGH level it will activate another SPDT relay contact and also will bring on an audible alarm. A thermistor is placed in the detection circuit in order to compensate for temperature variations. Built-in time delays on both ON or OFF relay operations avoid nuisance start-stops of fans or alarms. Units require 120V AC power. Because of possibly long storage time before it is initially energized, allow one week for unit to reach optimum operating conditions. If the unit was deenergized for a couple of days, the time required to have the unit back to normal operation is only a few minutes.

Typical specifications

Supply, install and connect at locations shown on drawings Acme Volatile Organic Compounds Detection And Control Unit model VOC-2. Units shall be fully electronic incorporating solid state circuitry with built-in temperature compensation, factory calibrated at LOW and HIGH levels. Provide SPDT control relay contacts for each level. Each unit shall include visual indicators for power “ON” and operating status. HIGH level shall activate an integral audible alarm. Unit enclosure shall be gasketed, made of corrosion resistant material. Power supply shall be 120V AC unless specified.

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